1. Field of the Invention
The present invention relates generally to security monitoring systems and, more particularly, to a security monitoring system that uses trajectories in a way to establish abnormal behavior and triggers an appropriate alarm in response thereto.
2. Prior Art
Security monitoring systems of the prior art, particularly residential security systems, utilize a box that monitors contact sensors for doors and windows and one or more infra-red sensors for area monitoring. When a contact is triggered or an infra-red sensor triggers, an alarm is sounded and a signal is sent via a data link such as a phone line to a central monitoring site. The central monitoring site typically initiates a set of phone calls, to the homeowner, to work, and/or to a designated neighbor to determine if the alarm signal was due to an unauthorized intruder or just to an accidental triggering by a family member or other authorized occupant of the structure.
If the alarm signal cannot be resolved by the phone calls, it is passed to the local police department. 95% of the calls passed to the police department turn out to be xe2x80x9cfalse alarmsxe2x80x9d in the sense that they were not due to an unauthorized intruder.
Therefore it is an object of the present invention to provide a security monitoring system which reduces the number of false alarms inherent in the prior art security monitoring systems.
It is a further object of the present invention to provide a security monitoring system that achieves the above objective while reducing the dependency of a central monitoring site to authenticate the validity of an alarm signal.
Accordingly, a security monitoring system is provided. The security monitoring system comprises: at least one camera for monitoring a path of an individual inside and/or outside a structure; a recorder for recording the monitoring of the individual; trajectory analysis means for computing a trajectory of the path of the individual from the recorded monitoring; comparison means for comparing the trajectory against known trajectories; and an alarm system for transmitting an alarm signal based on the comparison. Preferably, the at least one camera comprises a camera for each of an entrance, exit, and one or more rooms of the structure and the at least one camera is a video camera where the recorder records video segments of the path of the individual inside and/or outside the structure. More preferably, the alarm system transmits the alarm signal if the trajectory does not match one of the known trajectories and does not transmit the alarm signal if the trajectory does match one of the known trajectories.
In a preferred implementation of the security monitoring system of the present invention, the system further comprises: a database for storing image data for each authorized individual of the structure; and a recognition system for comparing images of the individual from the at least one camera with the stored image data in the database and for determining if the individual is one of the authorized individuals. The stored image data in the database are preferably face images in which case the recognition system is a face recognition system. In the preferred implementation, the alarm system transmits the alarm signal if the trajectory does not match one of the known trajectories and the individual is determined not to be one of the authorized individuals and does not transmit the alarm signal if the trajectory does match one of the known trajectories or the individual is determined to be one of the authorized individuals.
Also provided is a method for monitoring a structure. The method comprises the steps of: monitoring a path of an individual inside and/or outside the structure; recording the monitoring of the individual; computing a trajectory of the path of the individual from the monitoring; comparing the trajectory against known trajectories; and determining whether to transmit an alarm signal based on the comparison. The computing step preferably comprises computing the trajectory of the individual based on spatial and/or timing information derived from the monitoring. More preferably, the determining step comprises transmitting the alarm signal if the trajectory does not match one of the known trajectories and not transmitting the alarm signal if the trajectory does match one of the known trajectories.
In a preferred implementation of the method of the present invention, the method further comprises the steps of: storing image data for each authorized individual of the structure; and comparing images of the individual from the at least one camera with the stored image data in the database and for determining if the individual is one of the authorized individuals. In the preferred implementation, the determining step comprises transmitting the alarm signal if the trajectory does not match one of the known trajectories and the individual is determined not to be one of the authorized individuals and not transmitting the alarm signal if the trajectory does match one of the known trajectories or the individual is determined to be one of the authorized individuals.
In a yet more preferred implementation of the methods of the present invention, if the determining step determines that the trajectory does not match one of the known trajectories and the individual is determined to be one of the authorized individuals, the method further comprises the step of adding the trajectory to the known trajectories.